It is well known to transport trailers of trucks on railroad cars, namely, flat bed railroad cars. Some designs have used specialized structure railroad cars and adapters for the landing gear of semi-trailer trucks as illustrated in U.S. Pat. No. 2,864,321. Others have provided stands for the king pin of the trailer which ride along a pair of slots in the surface of the railroad car, and generally include a manually actuated mechanism to hold the stand in place on the car after adjustment. Examples of these structures are shown in U.S. Pat. Nos. 2,845,878; 2,846,172 and 2,903,977.
Collapsible fifth wheel stands have also been installed at one end of a flat bed and arranged to be raised by a chain pulled by a truck tractor beneath a parked trailer to secure it to the railroad car. This is shown in U.S. Pat. No. 3,202,390. Examples of stationary, collapsible fifth wheel stands which are raised or lowered by spring, screws or hydraulic include U.S. Pat. Nos. 3,180,282; 3,189,307; 3,291,074 and 3,289,987.
A self-propelled stanchion which can be positioned along the surface of the railroad car and raised and lowered using internal or external motors is described in my U.S. Pat. No. 4,718,800. But its operation was independent of the trailer positioning.
All of the systems of the prior art have advantages and disadvantages. Those which use specialized car design are not usable to transport other types of freight. Those which have erect stand are not as storable and require the removal of unused stands at one location and a supply at the unloading location if there is further loading to be performed. Some of the collapsible stands are not adjustable along the surface of the flat bed and, thus, do not allow for optimum placement of the maximum number of trailers on a train system. The positioning and securing of the stanchions require special equipment or more than one operator or plural steps in addition to positioning connecting and disconnecting the trailer.
Thus, it is an object of the present invention to provide a stanchion which is adjustable along the surface of a railroad car.
Another object of the present invention is to provide a stanchion system which reduces the number of steps in loading, securing, unsecuring and unloading a trailer on and from a railroad car.
Still another object of the present invention is to provide a system wherein the stanchion is repositioned and operated from the tractor which positions the trailer.
These and other objects of the invention are obtained by providing a stanchion with a latch system which is operable from the tractor which positions the trailer such that the tractor locks and unlocks the latch to appropriately reposition the stanchion during the positioning of the trailer. The stanchion includes a sled to which a stand is mounted. The latch is biased to be normally engaged to the rail car to prevent movement of the sled, and in response to an external force from the tractor disengages the rail car to prevent movement of the sled. The latch includes at least one dog and an operator or piston moving the dogs to disengage a railroad car in response to an external force. The operator and dogs are biased to the engaging position. The sled includes a channel which receives a horizontal portion of a track and the dogs engage the vertical portion of the track. The track includes a plurality of apertures in which the dogs are received.
An interlock is provided between the latch and the stand for permitting the latch to disengage from the railroad car only when the stand is in the lowered position. The interlock includes a cam connected to the latch and having a camming surface which has a first and second positions corresponding to the lock and unlocked position of the latch. A cam follower is connected to the stand for at least engaging the cam surface in the second position when the stand is in the lowered position. The cam follower disengages the cam surface in the first position when the stand is not in the raised position.
The tractor includes a gate having a locking and unlocking position. In the unlocking position, the gate engages the operator of the latch when the tractor is adjacent to the sled to apply the external force to unlock the latch. In the locking position, the gate does not apply the external force to the latch when the tractor is adjacent to the sled. The tractor also includes a hook which engages the stand for two purposes. First it is used during loading of the trailer to raise the stand of a latched or locked sled from its lowered to its raised position to engage and secure the tractor. Second, when the stand is in its lowered position and the tractor's unlocking gate is in its unlock position the hook engages the stand and prevents motion of the sled away from the adjacent tractor. With the sled and stand thus captured between the hook and the gate, any movement of the tractor in either forward or reverse direction, will be transmitted to the unlocked sled, and it will thus move with the tractor and be repositioned during the loading and unloading of the trailer by the tractor.
The hook may be a single element manipulated by an operator or may be a pair of links pivotally connected and moved between an extended and retracted position by an operator in combination with a third link. The hook is mounted on a slide block to the tractor, and a shock absorber is provided. This increases the ability to move the hook while the stand is in the raised position. The hook includes first and second members pivotally connected together to form the hook. A lock is provided having a first position for locking the first and second members into a hook configuration and a second position to allow first and second members to rotate relative to each other. Thus, when the hook is unlocked, the forward motion of the tractor relative to the stand will cause the two members to rotate relative to each other and release the hook configuration and the hook from the stand. Biasing means such as a spring is provided for biasing the first and second members into the hook configuration.
A method of loading and securing a trailer to the railroad car using the tractor includes positioning the trailer over a lowered stanchion on the surface of the railroad car. The trailer and stanchion are then repositioned to a desired position on the surface of the railroad car using the tractor. The tractor is disconnected from the trailer and the stanchion is raised by the tractor to connect and secure the trailer to the railroad car. Apparatus on the tractor as mentioned above is used to unlock the stanchion from the railroad car before the repositioning step and lock the stanchion after the repositioning step. Apparatus on the tractor activates a hook to hook a portion of the stanchion to the tractor before the raising step and to unhook the stanchion from the tractor after the raising step.
The method of unloading a trailer secured to a railroad car by a stanchion using a tractor includes positioning the tractor adjacent to the trailer and the stanchion. Next, the tractor disconnects the trailer from the stanchion and connects the trailer to the tractor. The tractor repositions the trailer and the stanchion to a desired position in which the stanchion is to be stowed, and finally removes the trailer from the railroad car.
The tractor disconnects the trailer from the stanchion by lowering the stanchion. The tractor unlocks the stanchion from the railroad car by applying an unlocking force before the repositioning step and relocks the stanchion to the railroad car after the repositioning step. A hook on the tractor engages the stanchion after it is unlocked and pulls it to its repositioned position and then unhooks from the stanchion before removing the trailer. The stanchion is repositioned to one end of the railroad car to be ready for the next loading operation.
Thus, the unique stanchion and its manipulation by the tractor allows the stanchion to be repositioned during loading and unloading, in order to secure the most efficient use of deck space on the train, as well as being raised and lowered. Similarly, all the operations, repositioning and controlling of the stanchion are performed from the tractor, thereby reducing the amount of time, the number of steps and the number of people involved in the loading and unloading of the trailer and the positioning and repositioning of the stanchion.